Automatic or semiautomatic telephone system



July 23, 1929.

C. STEWART ET AL Elaudius STE 111T? and Farnand Euhural Patented July 23, 1929.

GLAUDIUS STEWART AND FERNAND GOHOREL, OF PARIS, FRANCE, ASSIGNORS TO AUTOMATIC ELECTRIC INC., OF CHICAGO, ILLINOIS, A CORPORATION OF DELA- WARE.

AUTOMATIC OR SEMIAUTOMATIC TELEPHONE SYSTEM.

Application filed July 9, 1926, Serial No.

The present invention relates to automatic and semi-automatic telephone systems, and more particularly to systems in which there are manual exchanges as well as automatic exchanges having register translators for controlling the operation of selecting devices in the automatic exchanges, and its object is to effect in'iprovements in the devices for setting up calls from an automatic or semi-aw tomatic exchange to subscribers belonging to a manual exchange. An automatic exchange of the type referred to above is shown in United States Patent No. 1,720,348, to J. E. Ostline, issued July 9, 1929.

. The calls to a manual exchange are usi'lally received at a mono-cord which is connected by known means to one of the record ers of the incoming group, and when the wanted number is transmitted, it is recorded on a call indicator comprising luminous signals. At the same time a lamp associated with the mono-cord lights up to indicate the cord, on which a call has arrived. As soon as the plug of the mono-cord is inserted into the jack of the wanted subscriber, the connections with the recorder and with the call indicator are severed, and these devices be come free for other calls.

The invention relates to a mono-cord arranged in such a manner that the transmission of the figures of the wanted number is delayed until the mono-cord has been connected to an idle recorder. With this arrangement the preselectors, which are usually associated with each mono-cord, can be suppressed, and each recorder is provided with a cord seeker. This arrangement effects a considerable saving, because the nume ber of recorders is less than the number of mono-cords.

The invention likewise relates to an arrangement of mono-cord circuits, such that the calling current is automatically transmitted over the subscribers line even when the exchanges have the tip and the sleeve of the plug of the mono-cord short circuited momentarily when the plug is inserted into the jack of the wanted subscriber.

Furthermore the invention relates to arrangements, whereby the subscriber at the automatic exchange can recall the operator at the manual exchange.

The method of operating the system will now be described with reference to the annested drawing,

121,315, and in France August 14, 1925.

lVhen the auxiliary line is seized at the automatic exchange, the relay 1 is energized over its two windings in series with the loop of the outgoing line.

The relay 1, on energizing, at 2 closes the circuit of relay 3, and this relay, on enerizing, prepares at 4: the circuit for the impulses, and at 5 it prepares the calling circuit; at 6 it ensures the circuit of the relay 1, which would be open when the relay 8 is energize; at 6 it opens the engaged circuit of the auxiliary line; at 9 it puts earth on the starting lead of the mono-cord seeker, and at 5 it connects the relay 10 to the test lead at the bank of the cord seeker.

When earth is put'on the starting lead of the cord seekers, the relay 11 of the first ldle seeker is energized in the circuit. over battery, the relay 11,.back contact 12, a back contact of the busy key 13, the starting lead 1 1-, 15 9, 16, and earth. The relay 11 on energizing connects at 17 the relay 18 to the test Wiper 19 of the seeker, and at 20 it puts earth on the rotary magnet 21 of the seeker.

lVhen the test wiper reaches the contact of the mono-cord, on which there is a call, a circuit is closed for the relay 18 over earth, relay 18, 17, the wiper and the test contact of the sceker'19, the test lead 24:, 23, 5, 24', 25, the low resistance winding of relay 10, battery. The relays 10 and 18 are energized in series. I

The relay 18 on energizing opens at 12 the circuit of relay 11 and of the rotary magnet 21, and the wipers stop on the contacts of the mono-cord, on which there is a call. It opens at 26 the circuit for liberating the recorders;

at 26 it closes the circuit of relay 27; at 28 it closes a contact in the chain of contacts, and at 12 it prepares the starting circuit for the next seeker.

The relay 27 on energizing prepares at 29 the impulse'circuit, at 30 it prepares the circuit of the calling lamp of the mono-cord, and at 31 it closes the locking circuit of relay 18 over the test wiper.

The relay 11 being slow acting remains attracted long enough after its circuit has been opened at 12 to permit the relay 27 to operate and close at 31 the locking circuit for the relay 18; when the relay 11 falls back, the startinglead is switched over at 32 to the next seeker. I

At the mono-cord the relay 10 on energizing removes at 15 the earth on the stair-ting lead, it opens the circuit the high re I sistance winding of relay 8 in order to prevent this relay operating it all the recorders ing figures of the wanted subscribers numher. At contact the short circuit is removed from the high resistance winding of the relay 10in order to prevent another seeker stopping on the mono-cord. j

The method of recording the number is etl'ected as follows:

When the director commences to transmit the number of the wanted subscriber, at each opening of the auxiliary line, the relay 1 falls back and transmits one impulse to the rotary magnet of the recorder of the thousands over the following circuit; earth, 2, 4, the impulse lead 35, the wiper 36 of the cord seeker, 29, the relay 37, the wiper 38 of the register controller in position No. 1, the rotary magnet 39 of the thousands register and battery. Ateach impulse received, the magnet advances its wipers one contact. The relay 37 is energized in series with the recorder magnet, and being slow acting, it remains attracted during the train of impulses. At contact 40 the relay 37 closes the circuit of the rotary magnet 41 of the register controller over earth, 26, 42, 40, the rotary magnet 41 and battery. The magnet 41 is energized but does not move the wipers. The relay 3 is short circuited at each impulse, thereby rendering it slow acting and it remains in its operated position during the impulses. V I

An instant after the end of the first train of impulses the relay 37 falls back and opens the circuit of the rotary magnet 41 of the register controller. This magnet on falling back causes the wipers to pass into the second position.

In the second position the impulse circuit is connected by the wiper 38 to the hundreds recorder, and this recorder is positioned by the train of impulses for the hundreds digit.

In the third position of the controller, the tens digit is recorded, and in the fourth position the units digit is received.

Recording the number on the call indicator.

hen the registe1',,cont1'oller passes into the fifth position, the circuit of relay 43 is closed over earth, the relay 43, the wiper 38 in position live, the relay 37, 29, the Wiper 36 of the cord seeker, 35, 4, 2, a resistance and bat-' tery.

, Vhen the relay 43 is energized, it puts at 44 earth on the pilot lamp for waiting calls and on the windings of the relays 45, 46, and at 42 it puts earth on the starting lead of the register controller over the contacts 4748-. The register controller operates and advances the wipers. 11 the change over key of the indicator is in its normal position, there is battery on the wiper 49, and when this wiper reaches the contact of the recorder, on which the number has been completely recorded, the relay is energized in the circuit: battery, the back contact 50 of the change over key of the indicator, the wiper 49, the relay 45, 44 and earth.

The relay 45, on energizing, opensat 47 the circuit of the rotary magnet ol the register controller and the wipers stop on the contacts of the recorder. It puts at 52, 53, 54, earth on the wipers of the recorder having access to the indicator No. 1, and at 47 the circuit of the signalling lamp of the mono-cord is closed over eartl'i, 26, 42, 47, 30, the wiper 57 of the seeker, 58, the signalling lamp 56, and battery over a pilot relay. It the change over key be in its operated position, the relay 46 would be energized and the earth would be put on the wipers of the register having access to the indicator No. 2. The number is recorded on the call indicator and at the same time the signalling lamp at the mono-cord is light ed, at theone where there is the call.

Setting up the connection.

The operator tests the wanted line and it it be free she inserts the plug of the monocord into the multiple jack of the wanted subscriber.

Upon the insertion of the plug, the relay 59 is energized in series with the cut oil relay of the wantedsubscriber. At 23 it opens the circuit of the relay 10 at the mono-cord and of the relay 18 at the cord seeker; at 16 it removes earth from the contact 0 of relay 3, and at-16 it prepares the circuit of the relay 8, the locking circuit of relay G0 and the circuit of the supervisory lamp of the wanted subscrib er. At tll it closes another circuit for the relay 34; at (32 it prepares the circuit oi the supervisory lamp oi the calling subscriber, and at 63 it disconnects the tip oi the plug from the testing winding of the operators set and connects it to the contact of the ringing relay 60.

The relay 10 falls back an instant after its circuit has been opened at 23. On falling back, it closes at 64 the circuit of the relay 8 over earth, front contact 16, a listening key contact 65, ($4, the low resistance winding of the relay 8, battery. On energizing, the relay 8 at 6C) closes its locking circuit independently of the contact 64 and of the back contact of the listening key (55. At 7 it connects the impulse circuit to the relay 10 over the contacts 64, 7 and 5. At 67 it opens the first circuit for energizing the relay 1, and at 68 it prepares a busy circuit for the auxiliary line. At 24 it opens another point in the short circuit for the high resistance winding of the relay l0, and at 69 it closes the circuit for the ringing current.

The ringing current is transmitted to the v his line over ,the following circuit: battery, ringing generator, the ringing interrupter, the low resistance winding of the relay 60, 69, 5, 70, 63, 7 1, a line conductor, the bell at the wanted subscriber, the other line conductor, 72, 73, a resistance and earth. One part oi the ringing current passes over the condenser to the line of the calling subscriber. The relay 60 is not operated by the alternating current.

lVhen the wanted subscriber answers, a circuit is closed for continuous current superimposed on the ringing current and the relay 60 is operated. The relay 60 is energized and closes the circuit ofthe supervisory lamp asso- Uovwersation a ncl super-vision.

The relay 74: is then put in the circuit of the wanted station and is energized in series therewith. At 75 it opens the circuit of the supervisory lamp associated with the wanted party and at 76 it opens the circuit of the re lay 34:. On falling back, the relay 3d reverses the current in the auxiliary line for the purpose of metering and supervision.

Conversation then takes place over the two condensers in series with the line.

During the conversation, the wanted sub scriber can recall. the operator by moving his switch-hook up and down, thereby opening the circuit of the relay 7 which on falling back at 75 closes and opens the circuit of the wanted subscribers supervisory lamp.

The calling subscriber can recall the operator by dialling any number with his nun1- ber dial. The interruptions thereby effected in the auxiliary line cause the relay 1 to vibrate and the circuit of relay 10 is closed over earth, 2, l, 64, 7, 5, the relay 10 and battery. The relay 10 is energized, at 6% it closes a circuit for locking itself over a back contact of the listening key 65, and at 77 it puts i11- terrupted earth on the supervisory lamp. hen the operator depresses the listening key, the circuit of the relay 10 is opened and the relay 10 on falling back opens at 77 the circuit of the supervisory lamp.

At the end of the conversation, when the wanted subscriber hangs up his receiver, the relay 7 t falls back and the supervisory lamp of the anted subscriber is lighted in the following circuit: earth, 16, 75, 78, the lamp and battery over a pilot relay (not shown).

Vhen the calling subscriber hangs up his receiver, the loop over the auxiliary line is opened and the relays 1 and 3 can release in succession, and the circuit for the supervisory relay ot the calling subscriber is closed over earth, 2, 4, 77, 62, the lamp and battery over a pilot relay (not shown).

Until the operator withdraws the plug of the mono-cord, battery is put on the positive lead of the auxiliary line, in order to mark it engaged at the outgoing end over battery, a resistance, 68, 6 and the positive lead oi the auxiliary line.

When the operator withdraws the plug of the mono-cord, the relay 59 on falling back opens the circuit of the relays 8 and 60 and they release. Hence the mono-cord is free and is ready to receive another call.

Releasing the recorder.

\Vhen the relay 59 opens its contact 23, the relay 18 of the recorder falls back and opens at 26 the circuit of the relay 27, which falls back and opens the circuits for operating the recorder. At contact 26 is closed the circuit of the magnets of the recorder over the contacts 79, 80, 81, 82 and 83.

The magnets operate and cause the wipers oithe recorder to return to their normal position. At contact 12 the starting lead is connected to the relay 11 and the recorder is ready to receive another call.

Faulty calls.

If a subscriber does not completely transmit his call, the number transmitted, though incomplete, appears on the call indicator after a predetermined time, for example 30 seconds. w

Vlhen the relay 18 is energized, it puts earth over 26, 42 and l0 on the winding of the relay 8A. The latter receives battery over its contact 85 and the interrupter 86. lVhen the interrupter closes its Contact, the relay s4 is energized by its two windings in series and only operates the contacts 85 and 87. At contact 85 it closes its locking circuit and disconnects the interrupter 86, and at 87 it connects the circuit of the interrupter 88 to its low resistance winding. The interrupter 88 closes its contact 15 seconds after the interrupter 86, and at that moment the relay 8 operates all its contacts. At contact 89 the interrupter 88 is disconnected and at contact 90 the circuit of relay 43 is closed.

The relay 43, on energizing, causes the incomplete number to be recorded on the call indicator in'the manner already described.

The operator, on seeing the number indicated, can speak to the subscriber in order to ascertain the number of the wanted subscriber and if he be free she inserts the plug of the mono-cord into the multiple jack, thereby releasing the recorder and the call indicator.

Marking engaged the mono-cowl and am:- z'lz'arg lines.

If the operator finds a fault on a mono-cord, she can put it out of service by operating the busy key. Thereby the relay 8 is energized by its high resistance winding, and at 68 it I puts battery in series with a resistance on the positive lead of the auxiliary line. at the outgoing exchange a high resistance relay is energized by this battery and it puts earth on the test contact of the auxiliary line in order to mark it engaged.

If all the recorders of a group be engaged, the chain of contacts is closed and the circuits of the relay 8 at all the mono-cords are closed in order to mark engaged the corresponding lines at the outgoing exchange.

hen an operator leaves her position, on withdrawing herinstrument plug, the feeding relay of her instrument falls back and puts earth on the relays 8 of the mono-cords in order to mark them engaged at the outgoing end of the lines.

What is claimed is:

1. In a telephone system, a first and a second exchange, a trunk line extending from said first exchange to said second exchange, means for establishing a normal current flow over a conductor of said trunk line, a register at said second exchange common to said trunk line and other similar trunk lines, means automatically responsive to the establishment of said normal current flow over a conductor of said trunk line for connecting said register to said trunk line, and means responsive to the completion of said connection for reversing the direction of current over said one conductor of said trunk line.

2. In a telephone system, a first and a second exchange, a trunk line extending from said first exchange to said second exchange, means for establishing a normal current flow over the two conductors of said trunk line in series, a register at said second exchange, means responsive to the establishment of said current flow for connecting said register to said trunk line, and means responsive to the completion of said connection for reversing the direction of said current flow.

3. In a call indicator system, a plug ending trunk, a register, means responsive to the extension of a call over said trunk for connccting said register to said trunk, and a reversing relay for said trunk responsive to the completion of said connection.

4. In a telephone system, a trunk line terminating at an operators swtichboard, means for establishing a current flow over a conductor of said trunk line, a register, means responsive to series of momentary interruptions of said current flow corresponding to the digits of a called number for registering a called number on said register, operator controlled means for extending a connection from said trunk, line, a signal, and means responsive to an additional momentary interruption of the said current flow for causing the repeated and continued operation of said signal While said connection is maintained.

5. In a telephone system, a register and means for registering called numbers thereon, means responsive to the completion of the registration of a called number for display ing the called number, a first and a second constantly moving interrupter, a twostep relay for said register operated to its first step under the control of said first interrupter after the registration of a called number is started, means controlled by said relay in its first step for causing it to be operated subsequently in its second step under the control of said second interrupter, providing the registration of the called number is not completed, and means controlled by said relay in its second step for causing the display of the registered portion of the called number.

6. In a telephone system, a trunk line and means for establishing a flow of current in a conductor thereof, auxiliary equipment, means responsive to the establishment of said current flow for connecting said equipment With the trunk line at a point between the ends thereof, a relay operative responsive to the connection of said equipment with the trunk line for causing a reversal of said current flow, a signal, means for connecting said trunk line to a called line, and means operative when said trunk line is connected to a called line for placing said signal under the control of said relay and for rendering said relay controllable over said trunk line.

In Witness whereof, we hereunto subscribe our names this fifth day of June, A. D., 1926.

CLAUDIUS STEWVART. FERNAND GOHOREL 

